When the payment is made with automatic charging functionality, there is no user in the middle to define the repayment mode. Therefore, the default repayment mode is used.
Go to the Settings → Loan Settings → Credit products and click the pencil icon by the credit product name
In the emerged window, open the “Repayment modes” tab and click the “Add repayment mode” button
There is a star icon next to all repayment modes other than the “Initial payment” and “Payoff”.
The filled blue star means that this mode is the default one.
Click the star icon of any other mode, to make it default